Why Single phase induction motors are not self-starting?

Why Single phase induction motors are not self-starting?

Answer:

Single phase induction motors are not self-starting because a single-phase supply cannot produce a rotating magnetic field.

A rotating magnetic field is necessary for the motor to start and produce torque.

A single phase supply produces an alternating flux, which does not rotate and cancels itself out.

To create a rotating magnetic field, a two phase or three phase supply is required.